This work involves studies of lipids stored in human senile cataracts. Ceramides, sphingomyelin, and cholesterol have been found complexed to insoluble lens proteins and are believed to be causative of nuclear condensation of senile cataract. The ceramides and sphingomyelin which are increased in senile cataracts have abnormal fatty acid composition. Various subfractions of lens sphingolipids will be isolated and further characterization of cholesterol-protein complexes will be carried out. Methods to be utilized for identification of cataract sphinogomyelin subspecies will include thin-layer chromatography, and mass spectrometry. In addition, work on cataract-forming phospholipids found in aqueous humor will continue. The effects of lysophosphatidyl ethanolamine on cataract formation in rabbits will be tested. Phospholipids extracted from human retinal tissue will be tested for cataractogenic effects. This studies will determine whether retinal destruction which occurs in retinitis pigmentosa and allied disorders could release retinal phospholipids and thus induce the posterior subcapsular cataracts found in these disorders.